I prefer the kac handguard over the tropical as it doesn't have the flex(and don't like how small the original handguard is).
Do you want to throw a light or front grip on the gun? Do you want no flex or hell just like the look of the rail? If so go nuts. You shouldn't have a problem reselling it in the future if you decide you don't want it. Hell if the supply dries up again you could get your money back, they went for crazy money before kac agreed to make them again although I don't think that will be the case this time as a bunch were dropped on the market.